It appears that, to capture Evan Peters’ turn as the fast-moving son of Magneto, Singer is capturing footage in extreme slow motion. The end result of 3600 frames per second will appear 150 times slower than standard film and, as such, requires significantly more lighting to expose each frame. Although it’s hard to see exactly what he’s filming, you can check the basic setup in Singer’s image below.

The film is based on the comic book storyline “Days of Future Past,” which ran in Uncanny X-Men #141 and 142 back in 1981 during Chris Claremont and John Byrne’s run and introduced the idea of an alternate future for Marvel’s mutants that grew out of the Brotherhood of Evil Mutants killing an important senator, leading to a future where all mutants are hunted by Sentinels.